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1、INTERNATIONAL STANDARD First edition 1992-09-l 5 Nickel alloys - Flame atomic absorption spectrometric analysis - Part 7: Determination of aluminium content Alliages de nickel - Analyse par spectrometrie d absorption atomique dans /a flamme - Partie 7: Dosage de I aluminium Reference number IS0 7530
2、-7:1992( E) IS0 7530-7:1992(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body intere
3、sted in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnica
4、l Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75% of the member bodies casting a vote. I
5、nternational Standard IS0 7530-7 was prepared by Technical Committee ISO/TC 155, Nickel and nickel alloys, Sub-Committee SC 4, Analysis of nickel alloys. IS0 7530 consists of the following parts, under the general title Nickel alloys - Flame atomic absorption spectrometric analysis: - Part I: Genera
6、l requirements and sample dissolution - Part 2: Determination of cobalt content - Part 3: Determination of chromium content - Part 4: Determination of copper content - Part 5: Determination of iron content - Part 6: Determination of manganese content - Part 7: Determination of aluminium content - Pa
7、rt 8: Determination of silicon content - Part 9: Determination of vanadium content 0 IS0 1992 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
8、 the publisher. International Organization for Standardization Case Postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland ii -,-,- INTERNATIONAL STANDARD IS0 7530-7:1992(E) Nickel alloys - Flame atomic absorption spectrometric analysis - Part 7: Determination of aluminium content 1 Sco
9、pe This part of IS0 7530 specifies a flame atomic ab- sorption spectrometric method for the determination of aluminium in the range of 0,2 % (m/m) to 4 % z/m) in nickel alloys. Typical compositions of nickel alloys are given in annex B of IS0 7530-1:1990. The general requirements concerning the appa
10、r- atus, sampling, dissolution of the test sample, atomic absorption measurements, calculations and test report are given in IS0 7530-I. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of IS0 7530. At the tim
11、e of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this pat-t of IS0 7530 are encouraged to investi- gate the possibility of applying the most recent edi- tions of the standards indicated below. Members of IEC and IS0 mainta
12、in registers of currently valid International Standards. IS0 5725:1986, Precision of test methods - Determi- nafion of repeatability and reproducibility for a stan- dard fest method by infer-laboratory tests. IS0 7530-1:1990, Nickel alloys - Flame atomic ab- sorption specfromefric analysis - Part 1:
13、 General requirements and sample dissolution. 3 Principle Dissolution of a test portion in acid, filtration and aspiration of the test solution into a nitrous oxide- acetylene flame of an atomic absorption spectrometer. Combustion of the filter from the acid dissolution and volatilization of silica
14、with hydrofluoric acid. Fusion of the residue with potassium pyrosulfate, dissolution of the melt in dilute acid and aspiration of this second solution into a nitrous oxide-acetylene flame of an atomic absorption spectrometer. Measurement of the absorbance of the resonance line energy from the spect
15、rum of aluminim and comparison with that of calibration solutions at a wavelength of 309,3 nm. Addition of the results found in both solutions. 4 Reagents In addition to the reagents listed in IS0 7530-1, the following special reagents are required. 4.1 Hydrofluoric acid, p20 = I,15 g/ml. WARNING -
16、Hydrofluoric acid is extremely irritating and corrosive to skin and mucous membranes, producing severe skin burns which are slow to heal. In the case of contact with skin, wash well with wa- ter and seek medical advice. 4.2 Potassium pyrosulfate (Ke=,l,41 g/ml). Cool and make up to the mark with 7.1
17、.4.2 Secondary dilution for I,0 % (m/m) to 2,0 % (m/rrc) aluminium Pipette IO,0 ml of the solution from 7.1.3.2 into a 100 ml one-mark volumetric flask. Add 4 ml of the potassium chloride solution (4.3) and 9 ml of hydrochloric acid (p2, = I,18 g/ml). Dilute to 80 ml with water and add 4 ml of nitri
18、c acid kiFe; I,41 g/ml). Cool and make up to the mark with 2 -,-,- IS0 7530-7:1992(E) 7.1.4.3 Secondary dilution for 2,0 % (m/m) to 4,0 % (m/m) aluminium Pipette 5,0 ml of the solution from 7.1.3.2 into a 100 ml one-mark volumetric flask. Add 4 ml of the potassium chloride solution (4.3) and 9,5 ml
19、of hydrochloric acid (p20 = I,18 g/ml). Dilute to 80 ml with water and add 4 ml of nitric acid e;,1,41 g/ml). Cool and make up to the mark with 7.1.5 Processing the filter 7.1.5.1 Transfer the filter from 7.1.2 to a platinum crucible or dish (5.2). Dry, char and ignite to oxidize the carbon. Cool, a
20、dd 0,25 ml. of sulfuric acid (pgO = I,83 g/ml) diluted 1 + 1 and 1 ml of the hydrofluoric acid (4.1). Carefully evaporate to dryness and fuse the residue with 1 g of potassium pyrosulfate (4.2). Allow the melt to cool and dissolve it in a small volume of water containing approxi- mately 0,25 ml of h
21、ydrochloric acid $z,=l=iyng/ml). Heat, if necessary, to complete 7.1.5.2 Transfer the leach solution to a 100 ml one- mark volumetric flask and add 10 ml of hydrochloric acid (ppO = I,18 g/ml). Dilute with more water and add 4 ml of nitric acid (pzO = I,41 g/ml). Cool and make up to the mark with wa
22、ter. Proceed as di- rected in 7.4.1. NOTE 1 A very small amount of aluminium may be present in the fused residue but it usually does not exceed 0,5 mg. The solution is analysed separately and the alu- minium found is added to the main result. 7.2 Reagent blank solution Carry out a blank test in para
23、llel with the determi- nation, following the same procedure and using the same quantities of all the reagents. 7.3 Aluminium calibration solutions Using a burette, transfer to each of six 100 ml one- mark volumetric flasks, 0 ml, 5,0 ml, IO,0 ml, 15,0 ml, 20,O ml and 25,0 ml of the aluminium stan- d
24、ard solution (4.5). Add 4 ml of the potassium chlor- ide solution (4.3) and 4 ml of nitric acid (pzO = I,41 g/ml). Add sufficient hydrochloric acid (pzO = I,18 g/ml) to make its concentration 10 % (V/V ), cool and make up to the mark with wa- ter. These calibration solutions correspond to 0 mg/l, 5
25、mg/l, 10 mg/l, 15 mg/l, 20 mg/l and 25 mg/l of aluminium. NOTE 2 It is important that all the calibration solutions contain the same concentration of hydrochloric acid. The zero solution requires an addition of 10 ml of hydrochloric acid (pea = I,18 g/ml) and the last (25 mg/l of aluminium), which a
26、lready contains 2,5 ml of hydrochloric acid, re- quires an addition of 7,5 ml. 7.4 Calibration and determination 7.4.1 Atomic absorption measurements Proceed as directed in 7.4.1 of IS0 7530-1:1990, us- ing a wavelength of 309,3 nm and a nitrous oxide- acetylene flame. 7.4.2 Preparation of calibrati
27、on curves Proceed as directed in 7.4.2 of IS0 7530-1:1990. 7.5 Number of determinations Carry out the determination at least in duplicate. 8 Expression of results 8.1 Calculation Proceed as directed in 8.1 of IS0 7530-1:1990, using the atomic absorption measurements of the test solution (see 7.1.3.1
28、 or 7.1.4) and of the solution of the fused filter residue (see 7.1.5.2). Sum both per- centage results for aluminium. 8.2 Precision 8.2.1 Laboratory tests Six laboratories in four countries participated in the testing of this procedure using six samples of nom- inal composition given in table 1. 8.
29、2.2 Statistical analysis 8.2.2.1 Results were treated according to IS0 5725 as described in 8.2.2 of IS0 7530-1:1990. The results of this analysis are given in table2. 8.2.2.2 For sample 3920 one laboratory was re- jected as a Cochran outlier. For sample 7013 two laboratories were rejected, one as a
30、 Cochran and one as a Dixon outlier. However, the result which failed the Cochran test could be classified as a stat- istical straggler and would not have been rejected at the less critical test level given in IS0 5725. 9 Test report Refer to clause 9 of IS0 7530-1:1990. 3 -,-,- ISO 7530-7:1992(E) S
31、ample 825 902 3920 3927 7013 7049 Table 1 - Nominal composition of test samples % (m/m) Al co Cr cu Fe Mn Ni 02 0,07 21 136 30 0,7 Bal 034 0,05 5 0,04 48 0,4 Bal 0,15 2 19 O,l 3 073 Bal 091 1 20 0,05 44 0,4 Bal I,5 17 20 092 02 0,05 Bal 1 0,Ol 15 0,15 7 3,8 Bal Si Ti 034 I,1 0,35 2.5 W3 2,3 038 0.6
32、0,7 2,4 073 2.3 Table 2 - Results of statistical analysis Sample reference Mean Within-laboratory Between-laboratory % (m/m) standard deviation standard deviation Repeatability Reproducibility 825 0,169 0,005 2 0,011 4 0,014 7 0,035 4 902 0,434 0,004 5 0,007 5 0,012 7 0,024 8 3920 0,146 0,001 6 0,00
33、3 9 0,004 7 0,012 1 3927 0,109 0,003 2 0,004 6 0,009 1 0,015 9 7013 I,51 0,012 0 0,004 6 0,034 1 0,036 5 7049 0,972 0,008 7 0,008 6 0,024 5 0,034 5 4 -,-,- IS0 7530-7:1992(E) UDC 669.245543.422546.62 Descriptors: nickel alloys, chemical analysis, determination of content, aluminium, atomic absorption spectrometric method. Price based on 4 pages -,-,-